At present, photographic light-sensitive materials comprising a silver halide emulsion are utilized for various purposes in the market. The market scale has recently grown.
In this situation, photographic light-sensitive materials for use in a market that has a strong need for rapid delivery of a large amount of finished prints, such as photographic light-sensitive materials for color print in particular, requires an enhancement of the development speed which directly leads to an enhancement of print productivity. Thus, many studies have been made on the enhancement of development speed.
It has been known to increase the silver chloride content in the silver halide emulsion for the purpose of shortening the development time. The use of an emulsion having a high silver chloride content is described in JP-A-60-19140 (The term "JP-A" as used herein means an "unexamined published Japanese patent application"). In fact, the market shows a rapidly growing tendency to use a silver halide emulsion having a higher silver chloride content for color photographic paper.
However, the use of a high silver chloride emulsion has a great disadvantage in that it causes a great sensitivity change with the exposure temperature change, yielding great difficulty in supplying stably finished color prints to customers.
The relationship between the spectral sensitivity of a high silver chloride emulsion and the reduction potential of a spectral sensitizing dye used therefor is reported in "Photographic Science and Engineering", vol. 18, pp. 475-485, 1974, and "The Journal of Photographic Science", vol. 21, pp. 180-186, 1973. However, these articles do not refer to the relationship between the dependence of a high silver content emulsion on the exposure temperature and the reduction potential of a sensitizing dye used therefor.
Further, JP-A-2-42 discloses that the use of a sensitizing dye having a specified reduction potential improves the dependence of a high silver chloride content emulsion on the exposure temperature. However, the inventors found that the use of such a sensitizing dye causes a change in sensitivity and gradation with time after the preparation of a coating solution and before the coating thereof, and further improvements are needed to supply color photographic papers with stable properties to photofinishing laboratories.